1. Field of Invention
The invention relates to a deposition apparatus for organic light-emitting devices and, in particular, to a deposition apparatus having a substrate conveying system between chambers.
2. Related Art
An organic light-emitting device which is excited by electric current, has advantages of planar, high contrast, fast displaying speed, simplify structure, lighter, high outdoor visibility, low electrical consuming, and high luminance. Therefore, the organic light-emitting device is one of the most potential displays recently. However, organic light-emitting devices are not suitable for large-scale manufacturing. It is a big issue to develop an organic light-emitting device with long-term use.
Generally, manufacturing processes of an organic light-emitting device include three stages:                (1) After a cleaning step, a substrate is transferred into an anode deposition machine for depositing an anode layer, and a photolithography process is implemented to form a required anode circuit pattern;        (2) The substrate is transferred into a chamber with organic emitting material and a chamber with cathode material for depositing processes; and        (3) A moving box filled with vacuum or nitrogen is used to transfer the substrate into a passivation layer deposition chamber or a package machine, or a glove box is used to transfer the substrate into the passivation layer deposition chamber or package machine from the chamber with organic emitting material.        
A substrate carrier under ambient pressure condition out of vacuum is used to transfer substrates between each deposition chamber. During the transferring, substrates are loaded/unloaded from the substrate carrier all the time, and are polluted by water, oxygen, and particles in the air. In particular, organic emitting materials of organic light-emitting devices are very sensitive to water and oxygen. In the present research, water and oxygen are the major cause of damage of the organic light-emitting devices. They are also the major limitation why the current organic light-emitting devices cannot be commercialized. Therefore, it is the key point to avoid damage induced by water and oxygen during each process, so as to commercialize the manufacturing processes of organic light-emitting devices.
In addition, deposition process is implemented under a vacuum condition, so that the frequency of releasing vacuum, transferring substrates under ambient pressure, and exhausting gas is increased, so that the manufacturing time is increased. Furthermore, the conventional deposition apparatus or coating apparatus utilizes a robot arm (3-dimensional) to transfer the substrates, so time lost in transferring substrates is increased. Therefore, the throughput of deposition apparatuses is greatly reduced, and the deposition process becomes the chock point of the manufacturing and decreases the benefit of other process machines such as photolithography apparatuses and package apparatuses.
FIG. 1A and FIG. 1B are showing two conventional deposition apparatuses that are a cluster deposition apparatus and an in-line deposition apparatus, respectively. As shown in FIG. 1A, the cluster deposition apparatus is composite of a plurality of chambers 11, 12, 13, 14, 15, and 16, and a mechanical substrate transferring system 1. The mechanical substrate transferring system 1 further includes a robot arm 10. First, the robot arm 10 loads/unloads a substrate from the loading/unloading chamber 11. Then, the substrate is placed into each of the chambers 12, 13, 14, 15, and 16 in turn by the robot arm 10. In this case, because the loading/unloading chamber 11 has to store a lot of substrates (no more than 25 pieces of substrates in general) and has a big size, the cluster deposition apparatus may waste much time on exhausting gases. In addition, there are many idle chambers, so that the throughput of the cluster deposition apparatus cannot be raised efficiently. Moreover, in those idle chambers, some expensive organic materials are wasted.
Referring to FIG. 1B, another conventional deposition apparatus, an in-line deposition apparatus, is shown. In this case, robot arms 101 and conveying chambers 102 are used for transferring substrates. However, there are many substrates staying in the chambers 111, 121, 131, 141, 151, or 161. Because the chambers are too large, it wastes much time on exhausting gases.
As mentioned above, the present invention discloses a deposition apparatus for an organic light-emitting device, which includes a substrate conveying system and at least a chamber. The substrate conveying system is a circular turntable shape. The chambers are provided around the substrate conveying system in a specific order. While the substrate conveying system rotates in a circular direction, at least a substrate is transferred into the chambers for deposition. The substrate, a shadow mask and a shadow mask alignment system are positioned on a substrate carrier. After the deposition, at least a layer is deposited on each of the substrates. In this invention, a substrate conveying system with a circular turntable shape is used, so that time lost during substrate transferred is shortened, transferring stability is increased, time for deposition is reduced, possibility of substrate pollution is decreased, time lost during conveying in substrate carrier and loading/unloading is decreased, and the utility rate of organic materials is raised. Moreover, the cost of machines, cycle time of device manufacturing, and cost of device manufacturing are greatly decreased. As a result, the deposition apparatus of the invention can improve the throughput of organic light-emitting devices from 100˜300 sheet/day to more than 5,000 sheet/day.